U.S. patent number 7,335,424 [Application Number 11/141,306] was granted by the patent office on 2008-02-26 for ionomer laminates and articles formed from ionomer laminates.
This patent grant is currently assigned to ExxonMobil Chemical Patents Inc.. Invention is credited to Joseph D. Domine, Prasadarao Meka, Jeffrey Valentage.
United States Patent |
7,335,424 |
Domine , et al. |
February 26, 2008 |
Ionomer laminates and articles formed from ionomer laminates
Abstract
A co-extruded laminate of at least one layer of an ionomer and
at least one layer of an acid polymer that can be thermoformed with
a plastic substrate such as a polyolefin. The laminate can be
pigmented to eliminate the need to paint the surface of the plastic
substrate. Articles can be formed from the laminated substrate such
as automotive parts and sporting equipment.
Inventors: |
Domine; Joseph D. (Humble,
TX), Valentage; Jeffrey (Royal Oak, MI), Meka;
Prasadarao (Seabrook, TX) |
Assignee: |
ExxonMobil Chemical Patents
Inc. (Houston, TX)
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Family
ID: |
23070863 |
Appl.
No.: |
11/141,306 |
Filed: |
May 31, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050221077 A1 |
Oct 6, 2005 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10469072 |
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PCT/US02/08963 |
Mar 21, 2002 |
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60279911 |
Mar 29, 2001 |
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Current U.S.
Class: |
428/516; 428/520;
264/173.15; 264/173.14; 428/522; 264/173.11 |
Current CPC
Class: |
C08L
23/142 (20130101); C08L 23/0869 (20130101); B32B
27/32 (20130101); B29C 45/14811 (20130101); B32B
7/10 (20130101); C08L 23/04 (20130101); C08L
23/0815 (20130101); B32B 37/153 (20130101); B32B
27/08 (20130101); C08L 23/04 (20130101); C08L
2666/06 (20130101); C08L 23/0815 (20130101); C08L
2666/06 (20130101); C08L 23/0869 (20130101); C08L
2666/06 (20130101); C08L 23/142 (20130101); C08L
2666/06 (20130101); B32B 2323/10 (20130101); B32B
2605/08 (20130101); C08L 23/0876 (20130101); B32B
2323/046 (20130101); B29K 2715/006 (20130101); B32B
2323/043 (20130101); B32B 2307/4026 (20130101); Y10T
428/31855 (20150401); Y10T 428/25 (20150115); B32B
2307/558 (20130101); B32B 2307/584 (20130101); Y10T
428/31935 (20150401); B32B 2270/00 (20130101); B29L
2031/3044 (20130101); Y10T 428/31938 (20150401); C08L
2205/03 (20130101); B32B 38/12 (20130101); Y10T
428/31913 (20150401); Y10T 428/31928 (20150401); Y10T
428/31909 (20150401) |
Current International
Class: |
B32B
27/08 (20060101) |
Field of
Search: |
;428/516,520,522
;264/173.11,173.14,173.15 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
36 26 809 |
|
Dec 1987 |
|
DE |
|
4222832 |
|
Jan 1994 |
|
DE |
|
197 31 051 |
|
Jan 1999 |
|
DE |
|
0 342 244 |
|
Nov 1989 |
|
EP |
|
0 343 877 |
|
Nov 1989 |
|
EP |
|
0 721 856 |
|
Jul 1996 |
|
EP |
|
0 721 856 |
|
Jul 1996 |
|
EP |
|
0 630 746 |
|
Jul 1997 |
|
EP |
|
0 950 511 |
|
Oct 1999 |
|
EP |
|
0 635 360 |
|
Dec 1999 |
|
EP |
|
0 980 752 |
|
Feb 2000 |
|
EP |
|
1 038 788 |
|
Sep 2000 |
|
EP |
|
1 041 110 |
|
Oct 2000 |
|
EP |
|
0 642 921 |
|
Dec 2001 |
|
EP |
|
0 837 078 |
|
Aug 2002 |
|
EP |
|
1011981 |
|
Dec 1965 |
|
GB |
|
04 052136 |
|
Feb 1992 |
|
JP |
|
08 269409 |
|
Nov 1996 |
|
JP |
|
3-24954 |
|
Feb 1999 |
|
JP |
|
2000 016190 |
|
Jan 2000 |
|
JP |
|
2000-85062 |
|
Mar 2000 |
|
JP |
|
WO 95/04655 |
|
Feb 1995 |
|
WO |
|
WO 95/11929 |
|
May 1995 |
|
WO |
|
WO 95/19392 |
|
Jul 1995 |
|
WO |
|
WO 96/23009 |
|
Aug 1996 |
|
WO |
|
WO 96/30455 |
|
Oct 1996 |
|
WO |
|
WO 98/55296 |
|
Dec 1996 |
|
WO |
|
WO 97/02317 |
|
Jan 1997 |
|
WO |
|
WO 97/09358 |
|
Mar 1997 |
|
WO |
|
WO 97/09380 |
|
Mar 1997 |
|
WO |
|
WO 97/11995 |
|
Apr 1997 |
|
WO |
|
WO 97/27894 |
|
Aug 1997 |
|
WO |
|
WO 97/31976 |
|
Sep 1997 |
|
WO |
|
WO 97/35910 |
|
Oct 1997 |
|
WO |
|
WO 97/46381 |
|
Dec 1997 |
|
WO |
|
WO 97/46384 |
|
Dec 1997 |
|
WO |
|
WO 98/01291 |
|
Jan 1998 |
|
WO |
|
WO 98/02305 |
|
Jan 1998 |
|
WO |
|
WO 98/08902 |
|
Mar 1998 |
|
WO |
|
WO 98/24324 |
|
Jun 1998 |
|
WO |
|
WO 98/31549 |
|
Jul 1998 |
|
WO |
|
WO 98/32598 |
|
Jul 1998 |
|
WO |
|
WO 98/36003 |
|
Aug 1998 |
|
WO |
|
WO 98/03565 |
|
Nov 1998 |
|
WO |
|
WO 98/52981 |
|
Nov 1998 |
|
WO |
|
WO 99/07229 |
|
Feb 1999 |
|
WO |
|
WO 99/28791 |
|
Jun 1999 |
|
WO |
|
WO 99/51669 |
|
Oct 1999 |
|
WO |
|
WO 00/02724 |
|
Feb 2000 |
|
WO |
|
WO 00/07815 |
|
Feb 2000 |
|
WO |
|
WO 00/73148 |
|
Dec 2000 |
|
WO |
|
WO 01/74587 |
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Oct 2001 |
|
WO |
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WO 01/78981 |
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Oct 2001 |
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WO |
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WO 02/28957 |
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Apr 2002 |
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WO |
|
Other References
Abstract--Patent No. DE 197 31 051 (publ. Jan. 28, 1999). cited by
other .
Abstract--Patent No. EP 0 630 746 (publ. Jul. 23, 1997). cited by
other .
Abstract--Patent No. EP 0 635 360 (publ. Dec. 1, 1999). cited by
other .
Translation--Patent No. EP 0 721 856 B1 (publ. Jul. 17, 1996).
cited by other .
Translation--JP Application P2001-200069--filed Jan. 18, 2000.
cited by other .
Abstract--Patent No. JP 1901706, filed Jun. 30, 1986. cited by
other .
Abstract--Patent No. JP 49-129776, filed Dec. 12, 1974. cited by
other .
Abstract--Patent No. JP 56-146758, filed Nov. 14, 1981. cited by
other .
U.S. Appl. No. 10/472,871, filed Sep. 23, 2003, entitled "Ionomer
Laminates and Articles Formed From Ionomer Laminates", Domine et
al. cited by other .
Abstract, WO 00/02724 (published Feb. 20, 2000). cited by other
.
Abstract, WO 00/07815 (published Feb. 17, 2000). cited by other
.
Abstract for JP 2000 016190, published Jan. 18, 2000 (see line AJ).
cited by other .
Translation for DE 4222832, published Jan. 13, 1994 (see line AK).
cited by other .
U.S. Appl. No. Not Yet Assigned, filed May 31, 2005, entitled
"Ionomer Laminates and Articles Formed From Ionomer Laminates",
Domine et al. cited by other.
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Primary Examiner: Kiliman; Leszek
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of Ser. No. 10/469,072, filed
Aug. 25, 2003, now abandoned which is a National Stage Application
of International Application No. PCT/US02/08963, filed Mar. 21,
2002, which claims the benefit of Provisional Application No.
60/279,911, filed Mar. 29, 2001.
Claims
We claim:
1. A laminate suitable for applying to a polyolefin substrate
comprising: (a) at least one layer of ionomer; and (b) a tie-layer,
comprising a blend of an acid copolymer and a polyolefin, wherein
the at least one ionomer layer and tie-layer are secured to one
another to form a laminate and the melt indexes of adjacent
laminate layers are within less than 1 to 4 dg/min of one
another.
2. The laminate of claim 1, wherein at least one ionomer layer is
pigmented.
3. The laminate of claim 1, wherein the tie-layer acid copolymer
comprises an ethylene (meth)acrylic acid terpolymer.
4. The laminate of claim 1, wherein the tie layer blend comprises
an ethylene (meth)acrylic acid terpolymer and ethylene polymer.
5. The laminate of claim 1, wherein the polyolefin has a 1% secant
flexural modulus of from greater than 1000 MPa.
6. The laminate of claim 1, wherein the at least one ionomer layer
has a 1% secant flexural modulus of between 150 and 400 MPa.
7. The laminate of claim 1, wherein the tie-layer comprises from 30
wt % to 70 wt % ethylene polymer.
8. The laminate of claim 1, wherein the tie-layer comprises a blend
of acid copolymer and propylene polymer.
9. The laminate of claim 1, wherein the tie-layer comprises
propylene impact copolymer.
10. The laminate of claim 1, wherein the laminate is
co-extruded.
11. The laminate of claim 1, wherein the laminate is shaped.
12. The laminate of claim 11, wherein the laminate is shaped by
thermoforming the laminate.
13. An automotive component made from the laminate of claim 12.
14. A composite article suitable for an impact and scratch
resistant article comprising: (a) a laminate comprising a least one
layer of ionomer and a tie-layer, comprising a blend of an acid
copolymer and an ethylene polymer, wherein the at least one ionomer
layer and tie-layer are secured to one another to form a laminate
and the melt indexes of adjacent laminate layers are within less
than 1 to 4 dg/min of one another; and (b) a substrate secured to
the laminate to form the composite article wherein the substrate
comprises ethylene polymer.
15. The composite of claim 14, wherein the substrate has a 1%
secant flexural modulus of greater than 1000 MPa.
16. The composite of claim 14, wherein the acid polymer is an
ethylene (meth)acrylic acid terpolymer.
17. The composite of claim 14, wherein the tie-layer comprises from
30 wt % to 70 wt % ethylene polymer and from 70 wt % to 30 wt %
acid copolymer.
18. The composite of claim 14, wherein the ionomer comprises an
ethylene (meth)acrylic acid copolymer.
19. The composite of claim 14, wherein the ionomer comprises a
blend of Na and Zn salts of acid copolymers.
20. The composite of claim 14, wherein the laminate is
co-extruded.
21. The composite of claim 14, wherein the laminate is shaped.
22. The composite of claim 21, wherein the laminate is shaped by
thermoforming the laminate.
23. An automotive component made from the composite of claim
22.
24. A composite comprising: (a) a laminate comprising at least one
layer of ionomer and a tie-layer, wherein the at least one ionomer
layer and tie-layer are secured to one another to form a laminate;
and wherein the tie-layer comprises a blend of propylene polymer
and an acid polymer and the melt indexes of adjacent laminate
layers are within less than 1 to 4 dg/min of one another; and (b) a
substrate comprising polypropylene secured to the tie-layer of the
laminate to form the shaped composite.
25. The composite of claim 24, wherein at least one ionomer layer
is pigmented.
26. The composite of claim 24, wherein the melt indexes of adjacent
laminate layers are within less than 2 to 3 dg/min of one
another.
27. The composite of claim 24, wherein the propylene polymer is
present in the amount of 30 wt % to 70 wt % and the acid polymer is
present in the amount of 70 wt % to 30%.
28. The composite of claim 24, comprising at least two tie-layers
each comprising a blend of propylene polymer and an acid
polymer.
29. The composite of claim 24, wherein the propylene polymer is an
impact copolymer.
30. The composite of claim 24, wherein the ionomer comprises an
ethylene (meth)acrylic acid copolymer.
31. The composite of claim 24, wherein the ionomer comprises a
blend of Na and Zn salts of acid copolymers.
32. The composite of claim 24, wherein the substrate has a 1%
secant flexural modulus of greater than 1000 MPa.
33. The composite of claim 24, wherein the laminate is
co-extruded.
34. The composite of claim 24, wherein the laminate is shaped.
35. The composite of claim 34, wherein the laminate is shaped by
thermoforming the laminate.
36. An automotive component made from the composite of claim
35.
37. A method of forming a shaped laminate comprising: contacting at
least one layer of ionomer and a tie-layer, wherein the tie-layer
comprises a blend of an acid polymer and a polymer selected from
the group consisting of propylene polymer and ethylene polymer, and
the melt indexes of adjacent laminate layers are within less than 1
to 4 dg/min of one another; securing the at least one layer of
ionomer to the tie-layer to form a laminate; and shaping the
laminate.
38. The method of claim 37, wherein the at least one ionomer layer
is two ionomer layers.
39. The method of claim 37, wherein at least one ionomer layer is
pigmented.
40. The method of claim 37, wherein the propylene polymer is
present in the amount of 30 wt % to 70 wt % and the acid polymer is
present in the amount of 70 wt % to 30%.
41. The method of claim 37, wherein the shaping step is performed
by thermoforming the laminate.
42. The method of claim 41, wherein the laminate is thermoformed
into the shape of a desired end use article.
43. The method of claim 37, wherein the acid polymer comprises an
ethylene (meth)acrylic acid terpolymer.
44. The method of claim 37, wherein the tie-layer comprises a blend
of ethylene (meth)acrylic acid terpolymer, linear low density
polyethylene, and high density polyethylene.
45. The method of claim 37, wherein the laminate is
co-extruded.
46. An automotive component made from the method of claim 37.
47. A method of forming a composite article comprising: (a)
contacting at least one layer of ionomer and a tie-layer, wherein
the tie-layer comprises a blend of an acid polymer and a polymer
selected front the group consisting of propylene polymer and
ethylene polymer, and the melt indexes of adjacent laminate layers
are within less than 1 to 4 dg/min of one another; (c) securing the
at least one layer of ionomer to the tie-layer to form a laminate;
and (d) securing a substrate layer comprising polyolefin to the
tie-layer of the laminate to form the composite article.
48. The method of claim 47, wherein the at least one layer of
ionomer is two ionomer layers.
49. The laminate of claim 47, wherein at least one ionomer layer is
pigmented.
50. The method of claim 47, wherein the acid polymer is an ethylene
(meth)acrylic acid terpolymer.
51. The method of claim 47, wherein the securing step (d) is
further defined by injection molding the substrate to the
tie-layer.
52. The method of claim 47, wherein the securing step (d) is
further defined by spraying the substrate on the tie-layer.
53. The method of claim 47, wherein the substrate polyolefin is
selected from the group consisting of ethylene polymers, ethylene
copolymers, propylene polymers, propylene copolymers, propylene
impact copolymer and a blend of propylene impact copolymer and
ethylene plastomer, and mixtures thereof.
54. The method of claim 47, wherein the tie-layer comprises a blend
of ethylene (meth)acrylic acid terpolymer and a polyethylene.
55. The method of claim 47, wherein the tie-layer comprises a blend
of ethylene (meth)acrylic acid terpolymer, linear low density
polyethylene, and high density polyethylene.
56. The method of claim 47, wherein the substrate has a 1% secant
flexural modulus of greater than 1000 MPa.
57. The method of claim 47, wherein the melt indexes of adjacent
laminate layers are within less than 2 to 3 dg/min of one
another.
58. The method of claim 47, wherein the laminate is
co-extruded.
59. The method of claim 47, further comprising: (e) shaping the
laminate after step (c) and before step (d).
60. The method of claim 59, wherein the composite article is shaped
by thermoforming.
61. An automotive component made from the method of claim 59.
62. A composite suitable for impact and scratch resistant articles
formed by the method comprising: (a) forming a laminate comprising
at least two layers of material; wherein the melt index (MI) of the
layers are within 1 to 4 dg/min of one another; (b) forming the
laminate into a shape, the laminate having at least one layer of
ionomer and a tie-layer, wherein the at least one ionomer layer and
tie-layer contact one another to form the laminate and the
tie-layer comprises a blend of an acid copolymer and a polyolefin
polymer; and (c) securing a substrate layer comprising polyolefin
polymer to the laminate to form the composite article.
63. The composite of claim 62, wherein the laminate further has a
second ionomer layer, wherein the second ionomer layer is
co-extruded with at least the first ionomer layer.
64. The composite of claim 62, wherein the tie-layer acid copolymer
is an ethylene (meth)acrylic acid terpolymer and the polyolefin
present in the blend from 30 wt % to 70 wt % of the blend.
65. The composite of claim 62, wherein the tie-layer comprises an
(meth)acrylic acid terpolymer and the tie-layer polyolefin polymer
is selected from the group consisting of propylene polymer and
ethylene polymer.
66. The composite of claim 62, wherein at least one ionomer layer
is pigmented.
67. The composite of claim 62, wherein the securing step is further
defined by injection molding the substrate to the tie-layer.
68. The composite of claim 62, wherein the securing step is further
defined by spraying the substrate on the tie-layer.
69. The composite of claim 62, wherein the substrate polyolefin
polymer is selected from the group consisting of ethylene polymers,
ethylene copolymers, propylene polymers, propylene copolymers,
propylene impact copolymer and a blend of propylene impact
copolymer and ethylene plastomer, and mixtures thereof.
70. The composite of claim 62, wherein the substrate has a 1%
secant flexural modulus of greater than 1000 MPa.
71. The composite of claim 62, wherein the melt indexes of adjacent
laminate layers are within less than 2 to 3 dg/min of one
another.
72. The composite of claim 62, wherein the laminate is
co-extruded.
73. The composite of claim 62, wherein the laminate is shaped by
thermoforming the laminate.
74. An automotive component made from the composite of claim
62.
75. A method of forming a composite article comprising: (a)
contacting at least one layer of ionomer and a tie-layer, wherein
the comprises a blend of an acid copolymer and a polymer selected
from the group consisting of propylene polymer and ethylene
polymer, and the melt indexes of adjacent laminate layers are
within less than about 4 dg/min of one another; (c) securing the at
least one layer of ionomer to the tie-layer to form a laminate; and
(d) securing a substrate layer comprising polyolefin to the
tie-layer of the laminate to form the composite article, the
substrate layer selected from the group consisting of propylene
polymers and ethylene polymers.
76. A composite comprising: (a) a laminate comprising at least one
layer of ionomer and a tie-layer, wherein the at least one ionomer
layer and tie-layer are secured to one another to form a laminate;
and wherein the tie-layer comprises a blend of polymer and an acid
polymer, the tie-layer polymer selected from the group consisting
of propylene polymers and ethylene polymers and the melt indexes of
adjacent laminate layers are within less than about 4 dg/min of one
another; and (b) a substrate comprising polypropylene secured to
the tie-layer of the laminate to form the composite, the substrate
selected from the group consisting of propylene polymers and
ethylene polymers.
Description
FIELD OF THE INVENTION
The present invention relates to composites formed from ionomer and
acid polymer laminates contacted with a substrate material such as
a polyolefin, and methods of making the articles from shaped
ionomer/acid polymer laminates.
BACKGROUND OF THE INVENTION
Durable, glossy fascia associated with articles such as
automobiles, luggage, and other durable articles made from plastics
increase both the aesthetic appeal and the utility of these
articles. However, due to the physical characteristics of many
plastics such as polyethylene, polypropylene, polystyrene, etc., it
is often difficult if not impossible to color these external
surfaces with traditional paints and by common painting techniques.
Moreover, the paints themselves present an environmental problem,
and reduce the recyclability of the articles once painted. Thus,
there is considerable interest in developing new methods of
creating protective and decorative fascia for use on such
articles.
Ionomer materials are known in the art, and are known to be useful
in plastic films and for coating to various plastic substrates.
See, for example, U.S. Pat. Nos. 5,482,766, 4,148,972, 5,543,233,
4,800,130, 4,656,098, 5,206,294, 4,335,175; DE 36 26 809 A; EP 0
721 856; and JP 08269409, 2000085062, and 04052136. Ionomer
coatings are useful for their scratch and abrasion resistance, as
well as toughness and aesthetic appeal. A continued problem in the
use of ionomers is bonding the ionomer sheet or layer to a
substrate layer. This is particularly true where the substrate is
pre-formed and the ionomer must then be secured onto the substrate,
which is most often the case in current processes. For example,
when the substrate is an automobile bumper made from such materials
as polypropylene or ethylene-propylene copolymer, the substrate
material is typically injection molded to form the solid bumper in
a first step. In order to then color this bumper, it must either be
painted with traditional automotive paints, or some material must
otherwise be secured onto the bumper after it is formed, making it
impractical to secure multi-layered materials such as, for example,
laminated ionomer or ionomer layers, onto the bumper.
What is needed is a method of attaching a pre-pigmented material
such as an ionomer to a substrate, wherein the ionomer comprises
one or more layers that is pre-formed to the shape of the desired
end use article that allows the substrate to then be secured to the
shaped ionomer material.
SUMMARY OF THE INVENTION
These and other problems are solved by the present invention,
wherein a laminate is formed that can be shaped and secured to a
substrate, thus forming a composite article. The laminate includes
at least one layer of an ionomer, and a tie-layer that allows the
laminate to be secured to the substrate. The tie-layer may have at
least one layer of an acid polymer, or blend of acid polymer and
another material. The laminate, composite, and process of forming
the laminate and composition as disclosed herein eliminates the
need for painting and create a highly recyclable article. The
laminates of the invention are amenable to various processes known
in the art such as co-extrusion, thermoforming and injection
molding, and thus versatile.
One embodiment of the invention is a shaped laminate comprising at
least one layer of ionomer, a tie-layer having at least one layer
of an acid polymer, wherein the first layer and tie-layer contact
one another to form a shaped laminate. In another embodiment, the
shaped laminate may be further secured to a substrate to form the
shaped composite. At least one of the ionomer layers is pigmented
in a desirable embodiment.
The at least one tie-layer may be a blend of acid polymer and a
polyolefin, a soft-ionomer, a soft-ionomer and acid polymer blend,
a soft-ionomer and polyolefin blend, or any combination thereof.
Further, the tie-layer may have any number of layers of these
various materials. The polyolefin may include, for example,
polyethylene polymers, polyethylene copolymers, polypropylene
polymers, polypropylene copolymers, polypropylene impact copolymer
and a blend of polypropylene impact copolymer and ethylene
plastomer, and mixtures thereof. A desirable embodiment of the
tie-layer is single or double layer of a blend of polypropylene or
polyethylene with an acid terpolymer.
The substrate may be a polyolefin or other thermoplastic such as,
for example, polyethylene polymers, polyethylene copolymers,
polypropylene polymers, polypropylene copolymers, polypropylene
impact copolymer and a blend of polypropylene impact copolymer and
ethylene plastomer, wood, fiberglass, metal, and mixtures
thereof.
Also, the invention includes a method of forming a shaped laminate
and composite comprising thermoforming a laminate into the shape,
the laminate having at least one layer of ionomer and a tie-layer
having at least one layer of an acid polymer, wherein the first
layer and tie-layer contact one another to form the laminate.
Another embodiment includes the step of securing such as by, for
example, injection molding or painting a substrate layer to the
tie-layer of the laminate to form the shaped composite. The
laminate can be made by co-extrusion processes known in the
art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a representation of one embodiment of the laminate of the
invention;
FIG. 2 is a representation of one embodiment of the composite of
the invention; and
FIG. 3 is a representation of yet another embodiment of the
composite of the invention.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term "laminate" is used to refer to any number
of the same or different materials in film, sheet or layer form,
each layer being secured to one another by any appropriate means
such as by an inherent tendency of the materials to adhere to one
another, or by inducing the materials to adhere as by a heating,
radiative, process, or some other appropriate process. Some
non-limiting process examples of forming laminates are
co-extrusion, thermal lamination, or adhesive bonding, or some
combination thereof.
As used herein, the term "layer" is used to refer to each of the
one or more materials, the same or different, that are secured to
one another by any appropriate means such as by an inherent
tendency of the materials to adhere to one another, or by inducing
the materials to adhere as by a heating, radiative, chemical, or
some other appropriate process. The term "layer" is not limited to
detectable, discrete materials contacting one another in a finished
product such that a distinct boundary exists between the materials.
The term "layer" includes a finished product having a continuum of
materials throughout its thickness.
As used herein, in reference to "Groups", the new numbering scheme
for the Periodic Table Groups are used as in HAWLEY'S CONDENSED
CHEMICAL DICTIONARY 852 (13th ed. 1997).
Embodiments of the present invention include a tie-layer having at
least one acid polymer or blend of acid polymer and other materials
described further below, and its incorporation into a laminate with
at least one layer of an ionomer material. The laminate is formed
into a shape--such as by thermoforming in one embodiment--that is
consistent with a desirable end use article to be manufactured. The
shaped laminate is then combined with a plastic substrate material
such as a polyolefin to form a composite (hereinafter "composite")
or composite article (or "shaped composite") such as by an
injection molding process in one embodiment. The laminate layers
may be formed by any conventional method known to those skilled in
the art. One embodiment of the laminate and composite can be
described as shown in FIG. 1. In the embodiment in FIG. 1, I
represents the laminate having at least one ionomer layer a and a
tie-layer b. It is understood that the layers a and b are not meant
to be limited to only one layer, but each can be a multiple of
layers or blend of materials.
An embodiment of the composite of the invention is shown in FIG. 2,
wherein I represents the laminate having at least one ionomer layer
a and a tie-layer b and II represents the composite comprising the
laminate I and at least one substrate layer c. It is understood
that the layers a, b, and c are not meant to be limited to only one
layer, but each can be a multiple of layers or blends of
materials.
As an illustration of another embodiment of the composite of the
invention, a laminate and composite are shown in FIG. 3, wherein
the laminate I has at least two layers of ionomer a and a', and the
tie-layer has at least two layers of materials b and b', the
laminate being coupled to the substrate layer c, shown as a single
layer in this embodiment.
The tie-layer and substrate are contacted with one another to form
an area of adhesion between the two layers. In one embodiment, the
area of adhesion is uniform and continuous. Also, in another
embodiment, the final shaped composite article will be such that at
least part of the at least one ionomer layer will be exposed to the
external environment and be visible, while in another embodiment
part or all of the ionomer layer may not be exposed to the
environment or be seen. Below is a more detailed description of
each component of the laminate: the ionomer and at least one
tie-layer that make up I, and the substrate(s) layer that, together
with the ionomer and acid polymers, make up the composite II.
Ionomer
Ionomers used in the present invention are ionic compounds which
are copolymers of C.sub.2 to C.sub.4 .alpha.-olefin derived units
(ethylene is herein included as an ".alpha.-olefin"), and C.sub.3
to C.sub.6 .alpha.,.beta.-ethylenically unsaturated carboxylic
acids, and which contain one or more kinds of metallic ions
associated with the acidic pendant groups of the polymer. Typical
ionomers and methods of production are disclosed in, for example,
WO 98/52981, WO 95/11929. WO 96/23009, WO 97/11995, and WO
97/02317.
The uncomplexed metal ions suitable for forming the ionic
copolymers of the present invention comprise mono, di or tri-valent
metal ions in the Groups 1 through 13 of the Periodic Table of
Elements. Embodiments include the following metal ions: Na.sup.+,
K.sup.+, Li.sup.+, Cs.sup.+, Ag.sup.+, Hg.sup.+, Cu.sup.+,
Be.sup.2+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, Cu.sup.2+,
Cd.sup.2+, Hg.sup.2+, Pb.sup.2+, Fe.sup.2+, Co.sup.2+, Ni.sup.2+,
Zn.sup.2+, Al.sup.2+ Sc.sup.3+, Fe.sup.3+, Al.sup.3+ and Yt.sup.3+.
In the various ions mentioned above, Mg.sup.2+, Na.sup.+ and
Zn.sup.2+ are metals used in desirable embodiments. Reaction of the
carboxylic acid groups of the ionomer and a metal ion derived from
a desirable metal compound (metal oxide, metal chloride, etc.) is
referred to as "neutralization".
The ionomers used in this invention generally include more than 50
wt % in one embodiment, and from 75 to 95 wt % in another
embodiment, of .alpha.-olefin derived units and from 5 to 25 wt %
of .alpha.,.beta.-ethylenically unsaturated carboxylic acid derived
units.
One embodiment of an ionomer can be described as below in the
following structure (1):
##STR00001## wherein X.sub.1 and X.sub.2 can be the same or
different and are hydrogen or a C.sub.1 to C.sub.6 alkyl, and
Mn.sup.+ is a metal ion or NH.sub.4.sup.+. Of course, it is
understood that when n is 2-4, such as with a divalent metal ion
such as Zn.sup.2+, that charge neutrality for the ionomer is
achieved by reaction with a total of n acid groups from either the
same polymer chain, or an adjacent polymer chain. The diagram (1)
is not intended to be construed that the ionomer is a block
copolymer or limited to being a block copolymer. The values of i,
j, and k are determined by the following relationships (2) and
(3):
##EQU00001## wherein Q is from 10 to 40% of the polymer units
derived from the acidic monomer(s) relative to the total weight of
the ionomer in one embodiment, and from 15 to 20% of polymer units
derived from the acidic monomer(s) in another embodiment, and P is
from 10 to 50% of the acidic groups neutralized with the metallic
ions in one embodiment, and from 20 to 40% of the acidic groups
neutralized with the metallic ions in another embodiment. The
polymer component i, derived from ethylene in one embodiment, can
be linear or branched.
Ideal ionomers should be capable of being formed into a sheet or
skin, have a high scratch resistance, a high gloss, and a high
abrasion resistance. Embodiments of the ionomer have a melt
temperature of between 80.degree. C. and 88.degree. C., and a melt
index (MI) of between 0.5 and 3 dg/min (ASTM D1238, 190/2.16) in
one embodiment, and from 0.8 to 2.5 dg/min in another embodiment.
The ionomers have a 1% secant flexural modulus (ASTM D-790) of
between 150 and 400 MPa in one embodiment, and from 200 to 350 MPa
in another embodiment. Desirable ionomers are ethylene acrylic acid
copolymer ionomers and the like.
Other examples of ionomers include, but are not limited to,
butadiene-acrylic acid copolymer ionomers, perfluorsulfonate
ionomers, perfluorocarboxylate ionomers, telechelic polybutadiene
ionomers, sulfonated ethylene-propylene-diene terpolymer ionomers,
styrene-acrylic acid copolymer ionomers, sulfonated polystyrene
ionomers, sulfonated polypentenamer ionomers, telechelic
polyisobutylene sulfonated ionomers, alkyl methacrylate-sulfonate
copolymer ionomers, styrene-based polyampholytes ionomers and
acid-amine ionomers and the like. Typical examples of ionomers
employing salts of carboxylic acid type pendent groups are
disclosed in British Patent No. 1,011,981; U.S. Pat. Nos.
3,264,272; 3,322,734; 3,338,734; 3,355,319; 3,522,222; and
3,522,223. Typical examples of ionomers employing phosphonate-type
pendent groups include those disclosed in U.S. Pat. Nos. 3,094,144;
2,764,563, 3,097,194; and 3,255,130. Typical examples of ionomers
employing sulfonate-type pendent groups include those disclosed in
U.S. Pat. Nos. 2,714,605; 3,072,618; and 3,205,285. Other ionomers
are disclosed generally in U.S. Pat. Nos. 5,631,328, 5,631,328,
5,554,698, 4,801,649, 5,320,905, 5,973,046, and 4,569,865.
Ionomers comprising copolymers ethylene derived units and acrylic
acid (AA), derived units are desirable. As shown in Table 1,
examples of commercially available ionomers include, but are not
limited to, IOTEK series (ExxonMobil Chemical Company, Houston,
Tex.), such as IOTEK 8000, a 45% sodium neutralized ethylene-based
ionomer of 15 wt % acrylic acid (prior to neutralization), and
IOTEK 7030, a 25% zinc neutralized ethylene-based ionomer of 15 wt
% acrylic acid, and SURLYN resins (DuPont Company, Wilmington,
Del.).
One or more ionomer layers may contain additives such as
antioxidants, pigments or dies, and other agents. In one
embodiment, at least one layer of ionomer in the final composite
will have a pigment, antioxidant, or other additives. For external
uses, it is desirable to add a UV stabilizer such as TINUVEN 791
(CIBA Specialty Chemicals) or UVASIL 2000 HM or LM (Great Lakes
Chemicals), both silicon based compositions. Also, for scratch
resistance, it is advantageous to add siloxane based compositions
such as MB50-001 and/or MB50-321 (Dow Corning Corporation).
Effective levels are known in the art and depend on the details of
the base polymers, the fabrication mode and the end application. In
addition, hydrogenated and/or petroleum hydrocarbon resins and
other plasticizers may be used as modifiers.
Other examples include one or more of the following: heat
stabilizers or antioxidants, neutralizers, slip agents, antiblock
agents, pigments, antifogging agents, antistatic agents,
clarifiers, nucleating agents, ultraviolet absorbers or light
stabilizers, fillers, rosins or rosin esters, waxes, additional
plasticizers and other additives in conventional amounts.
Tie-Layer
In one embodiment of the invention, the tie-layer material b (or b
and b', etc) is an acid polymer, and can comprise one layer or more
of identical or different acid polymers. In another embodiment, the
tie-layer material can be a blend of an acid polymer and another
polymer such as an .alpha.-olefinic polymer or other thermoplastic
as described further below ("Substrate").
Acid polymers represent a broad classification of compounds
typically formed by the copolymerization of unsaturated carboxylic
acid and at least one .alpha.-olefin. Desirably, the carboxylic
acid may be formed from a carboxylic acid alone or in combination
with an ester. More particularly, the acid polymer may be an acid
terpolymer represented by the structure (4):
##STR00002## wherein X.sub.1 and X.sub.2 can be the same or
different and are hydrogen or a C.sub.1 to C.sub.6 alkyl, R can be
a C.sub.1 to C.sub.10 normal alkyl or branched alkyl in one
embodiment, and a C.sub.1 to C.sub.4 normal alkyl or branched alkyl
in another embodiment, j has a value of from 5 to 15% relative to
the acid terpolymer weight, and k has a value of from 5 to 25%, and
i has a value of from 65 to 90%. In one embodiment, the acid
polymer may be partially neutralized, creating a so called "soft
ionomer", or partially neutralized acid polymer. The neutralized
carboxylic acid groups can be characterized as above for the
ionomer. So called soft ionomers are disclosed in, for example, WO
97/02317.
In one embodiment of the invention, the acid polymers are acid
terpolymers, which comprise copolymers of ethylene, a lower alkyl
acrylate, particularly methyl acrylate, and an acrylic acid, such
as disclosed in U.S. Pat. Nos. 5,397,833, and 5,281,651. Other acid
polymers are disclosed in U.S. Pat. Nos. 4,307,211, and
5,089,332.
One embodiment of the acid polymer used in the present invention is
an ethylene/methyl acrylate/acrylic acid (E/MA/AA) terpolymer (or
"EAAT") comprising an acrylate content of from 4 to 40 wt % based
on the weight of the entire polymer, from 5 to 35 wt % in another
embodiment. The acrylic acid derived unit content is from 1 to 10
wt % in one embodiment, and from 2 to 8 wt % in another embodiment.
The remainder of the terpolymer comprises ethylene derived
units.
The E/MA/AA terpolymer may comprise a wide range of melt indexes,
generally between 0.1 to 30 dg/min in one embodiment, and from 1 to
10 dg/min in another (ASTM D1238, 190/2.16). Acrylates that are
particularly useful in the acid terpolymers are lower alkyl
(C.sub.1 to C.sub.4) acrylate esters.
As shown in Table 1, commercial examples of acid polymers include,
but are not limited to, ESCOR AT-310 resin having 6.5 wt % methyl
acrylate derived units and 6.5 wt % acrylic acid derived units, and
ESCOR AT-320 having 18 wt % methyl acrylate derived units and 6 wt
% acrylic acid derived units, both are ethylene acid, terpolymers
(ExxonMobil Chemical Company, Houston, Tex.). Soft ionomers are
commercially available as IOTEK 7510, a 69% zinc neutralized acid
terpolymer of 6 wt % acrylic acid and 20 wt % methacrylic acid
(prior to neutralization), and IOTEK 7520, a 43% neutralized acid
terpolymer of 6 wt % acrylic acid and 20 wt % methyl acrylate, also
available from ExxonMobil Chemical Company.
Acid polymers, or blends of the acid polymer with another polymer,
are embodiments of the tie-layer materials as described in FIGS. 1
through 3. In one embodiment, the tie-layer is made from an acid
polymer and a high density polyethylene polymer blend. In another
embodiment, the tie-layer is a acid polymer and a high density
polypropylene blend.
The tie-layer may also include additives such as pigments, dyes,
antioxidants, antiozonants, and other agents to improve its
performance. Examples include one or more of the following: heat
stabilizers or antioxidants, neutralizers, slip agents, antiblock
agents, pigments, antifogging agents, antistatic agents,
clarifiers, nucleating agents, ultraviolet absorbers or light
stabilizers, fillers, rosins or rosin esters, waxes, additional
plasticizers and other additives in conventional amounts.
Substrate
In one embodiment of the invention, the substrate is a polyolefin.
One class of polyolefins useful in this invention are thermoplastic
polyolefins. Thermoplastic polyolefins are a desirable substrate
material. Thermoplastic Polyolefins (TPOs) are a class of materials
including blends of polypropylene and a rubber phase such as EPDM
(ethylene-propylene-diene monomer) or EP (ethylene-propylene
rubber). The TPO's can be made either by physical blending or
in-situ reactor-made. The industry definition of TPO's typically
covers blends of greater than 20 wt % rubber phase, whether made by
physical blending or reactor-made.
These thermoplastic polyolefins may be homopolymers, copolymers, or
a combination thereof. These thermoplastic polyolefins may be
blended with the acid polymers described above and/or with
modifiers, described in greater detail below. More particularly,
these thermoplastic polymers may be linear or branched polymers and
include polyethylene polymers, polyethylene copolymers,
polypropylene polymers and polypropylene copolymers. Suitable
comonomer reactants may include one or a combination of either
ethylene, C.sub.3-C.sub.30 .alpha.-olefins or diolefins. Examples
of diolefins include .alpha.,.omega.-diene and more particularly,
.alpha.,.omega.-dienes that contain at least 7 carbon atoms and
have up to about 30 carbon atoms. Representative examples of such
.alpha.,.omega.-dienes include 1,6-heptadiene, 1,7-octadiene,
1,8-nonadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene,
1,12-tridecadiene, 1,13-tetradecadiene, and the like. Additionally,
.alpha.,.omega.-dienes containing aliphatic, cyclic or aromatic
substituents may also be used. Other useful substrate materials are
the class of dynamically vulcanized alloys of nylon and copolymers
of isobutylene and p-methylstyrene.
Another suitable substrate material is a so called plastomer,
which, in one embodiment is a copolymer and a C.sub.3 to C.sub.10
.alpha.-olefin and ethylene having a density in the range of less
than 0.915 g/cm.sup.3. In another embodiment, the plastomer useful
in the invention has a density in the range of from 0.85 to 0.97
g/cm.sup.3 and a melt index (MI) between 0.10 and 20 dg/min.
Plastomers can also be described as metallocene catalyzed
copolymers of ethylene and higher .alpha.-olefin comonomers such as
propylene, 1-butene, 1-hexene and 1-octene, and which contain
enough of one or more of these comonomers to yield a density
between 0.85 and 0.915 g/cm.sup.3. An example of a commercially
available plastomer is EXACT 4150, a copolymer of ethylene and
1-hexene, the 1-hexene derived units making up 18.5 wt % of the
plastomer (ExxonMobil Chemical Company, Houston, Tex.).
Desirably, the substrate has a melt flow rate of greater than or
equal to 20 dg/min, a high stiffness (1% secant flexural modulus)
of 150 kpsi (1000 MPa) or higher, and cold temperature ductility at
-30.degree. C. at 5 mph (133 m/min). Some commercially available
painted TPO materials only have ductility down to 0.degree. C. at 5
mph (133 m/min), while PP8244 (ExxonMobil Chemical Company) with
ionomer film shows ductility to -30.degree. C. at 15 mph (400
m/min). Thus, this embodiment of the present invention would be an
improvement over painted TPO substrates of the prior art.
Polyethylene and polypropylene copolymers and homopolymers are
desirable substrates. The polyethylene polymers may include low
density polyethylene (LDPE), linear low density polyethylene
(LLDPE), high density polyethylene (HDPE). These ethylene polymers
are well known in the art and include both ethylene homopolymers
and copolymers with higher .alpha.-olefins. As shown in Table 1,
examples of polyethylene polymers include: HD9856B resin, a broad
molecular weight bimodal homopolymer; EXCEED 357C32 resin, an
ethylene/hexene copolymer; HD-6908, a narrow molecular weight
homopolymer; LL-6201, a LLDPE, an ethylene-butene copolymer, and
EXACT plastomers, lower density ethylene-butene copolymers, all
available from ExxonMobil Chemical Company (Houston, Tex.).
The polypropylene polymers may include polypropylene random
copolymers, polypropylene impact copolymers and blends thereof with
ethylene plastomers and elastomers. Ethylene plastomers and
elastomers may be linear or branched and may be formed from a
copolymer of ethylene and one or more C.sub.3-C.sub.16
.alpha.-olefins. Such plastomers and elastomers may be blended, for
example with a polypropylene polymer. Examples of polypropylene
polymers include impact copolymers such as ESCORENE PP7032E2 and
PP8102E3 resins and ExxonMobil PP8114 and PP8224 resins, a blend of
a plastomer and impact copolymer having 69 wt % polypropylene, 14.1
wt % ethylene-propylene rubber, and 17 wt % ethylene-hexene
plastomer, are all available from ExxonMobil Chemical Company
(Houston, Tex.).
Finally, the substrate may be any other material such as
fiberglass, wood, glass, etched glass, aluminum, steel or other
metal substrates.
Lamination Process
The tie-layer and at least one ionomer layer described above may be
adhered to one another by any appropriate means to form the
laminate. In one embodiment, the ionomer layer is adhered to the
acid polymer layer in a co-extrusion process. The co-extrusion
process can include a 2, 3, 4 or more co-extruded layers. In
general, the process includes first melting each material in an
appropriate device and depositing or extruding these molten or
semi-molten materials together through a die. The various layers
can be combined in the melt stage via appropriate mechanisms known
in the art prior to exiting the die, or combined after exiting the
die. This is followed by contacting the thus formed multi-layered
laminate with a series of chill rolls and sheet conveyer. The
cooled laminate is then cut to size or rolled by appropriate
means.
The ionomer, acid polymer and other materials that form the
laminate of the present invention can be extruded using
conventional equipment well known in the industry. In one
embodiment, the extrusion process conditions are as follows. The
temperature controllers of the extruder(s) used to process the
ionomer(s) for the a layer(s) are set at 180.degree. C. to
225.degree. C. in one embodiment (and in the examples below),
yielding a final material melt temperature of 200.degree. C. to
215.degree. C. The temperature controllers of the extruder(s) used
to process the acid polymer(s) for the b layer(s) are set for
195.degree. C. to 225.degree. C. in another embodiment, yielding a
final material melt temperature of 210.degree. C. to 230.degree. C.
(and in the examples below). It is desirable that the viscosity of
each material to be extruded be closely matched to each other for
high gloss and color compatibility.
The final laminate may have any number of layers of ionomer and or
tie-layer materials. Embodiments of the laminate include one layer
of ionomer and one layer of an acid polymer. Another embodiment
includes two layers of ionomer and one layer of an acid polymer.
Yet another embodiment of the laminate includes two layers of
ionomer and two layers of tie-layer material such as an acid
polymer and/or blend of acid polymer and polyolefin. In yet another
embodiment of the laminate, there may be two layers on ionomer and
one layer an acid polymer/polyolefin blend as the tie-layer.
As an example of one embodiment of the laminate of the invention,
two layers of ionomer may be co-extruded with one layer of
tie-layer material, wherein the ionomers are Zn.sup.2+ and Na.sup.+
salts of ethylene acrylic acid copolymers and the tie-layer
material is ethylene acrylic acid terpolymer (or "EAAT"). Another
embodiment includes two ionomer layers of Zn.sup.2+ and Na.sup.+
salts of ethylene acrylic acid copolymers and a tie-layer including
a polypropylene/acid terpolymer blend such as, for example, a
polypropylene impact copolymer present from 10 to 90 wt % in one
embodiment, and from 30 to 70 wt % in another embodiment, and from
40 to 60 wt % in yet another embodiment in the blend, and EAAT
present from 10 to 90 wt % in one embodiment, from 30 to 70 wt % in
another embodiment, and from 40 to 60 wt % in yet another
embodiment in the blend.
In yet another example of the laminate, two ionomer layers as
described above may be present with one layer of tie-layer
material, the tie-layer including a blend of high density
polyethylene (HDPE) and EAAT. The HDPE may be present in the range
from 10 to 90 wt % in one embodiment, from 25 to 75 wt % in another
embodiment, and from 35 to 65 wt % in yet another embodiment, while
the EAAT is present in the range from 10 to 90 wt % in one
embodiment, from 25 to 75 wt % in another embodiment, and from 35
to 65 wt % in yet another embodiment.
In yet another example of the laminate, two ionomer layers may be
present with one tie-layer material, wherein the tie-layer material
is a blend of the following: HDPE and linear low density
polyethylene (LLDPE) in a ratio of from 75/25 wt % to 85/15 wt %,
blended with EAAT, the EAAT present in the tie-layer blend from 10
to 90 wt % in one embodiment, from 25 to 75 wt % in another
embodiment, and from 35 to 65 wt % in yet another embodiment.
In yet another example of the laminate, two ionomer layers may be
present with one tie-layer material, wherein the tie-layer material
is a blend of the following: linear low density polyethylene
blended with EAAT, the EAAT present in the tie-layer blend from 10
to 90 wt % in one embodiment, from 25 to 75 wt % in another
embodiment, and from 35 to 65 wt % in vet another embodiment.
In yet another example of the laminate, two layers of ionomer as
described above may be co-extruded with two layers of tie-layer
material. Examples of this tie-layer configuration include one
layer of an ethylene acrylic acid terpolymer and another layer of a
blend of polypropylene and acid polymer, specifically, a
polypropylene impact copolymer present from 10 to 90 wt % in one
embodiment, and from 30 to 70 wt % in another embodiment, and from
40 to 60 wt % in yet another embodiment in the blend, and ethylene
acrylic acid terpolymer present from 10 to 90 wt % in one
embodiment, from 30 to 70 wt % in another embodiment, and from 40
to 60 wt % in yet another embodiment in the blend.
The final laminate may have any number of layers of ionomer and
tie-layer materials. In one embodiment, the laminate is two layers,
three in another embodiment, and four layers in yet another
embodiment. In one embodiment, the ionomer layer or layers, prior
to thermoforming, are from 13 to 1000 .mu.m. In another embodiment,
the pre-thermoformed ionomer layer or layers is from 25 to 380
.mu.m. In yet another embodiment, the pre-thermoformed ionomer
layer is from 200 to 380 .mu.m. The tie-layer can be of comparable
thickness ranges, making the overall thickness of the laminate from
0.1 mm to 5 mm in one embodiment, or from 0.25 to 3 mm in yet
another embodiment.
In an embodiment of the laminate, the melt viscosity (MI) of each
laminate layer is within 1 and 4 MI (dg/min) of the layer in which
it is in direct contact with during co-extrusion, and within 2 and
3 MI (dg/min) in another embodiment. Composites with the desired
appearance and adhesion can be produced with compounds in the range
of 2 and 5 MI (dg/min).
Thermoforming Process
Thermoforming is a process of forming at least one pliable plastic
sheet into a desired shape. In an embodiment of the present
invention, the laminate that is formed from the at least one
ionomer layer and tie-layer are thermoformed into a desirable
shape, typically the shape of the end use article. An embodiment of
the thermoforming sequence is described. First, the co-extruded
laminate of ionomer and acid polymer (or other tie-layer materials)
is placed on a shuttle rack to hold it during heating. The shuttle
rack indexes into the oven which pre-heats the film before forming.
Once the film is heated, the shuttle rack indexes back to the
thermal forming tool. The film is then vacuumed onto the forming
tool to hold it in place and the forming tool is closed. The
forming tool can be either "male" or "female" type tools. The tool
stays closed to cool the film and the tool is then opened. The
shaped laminate is then removed from the tool.
Thermoforming is accomplished by vacuum, positive air pressure,
plug-assisted vacuum forming, or combinations and variations of
these, once the sheet of material reaches thermoforming temperature
of 170.degree. C. to 185.degree. C. A pre-stretched bubble step is
used, especially on large parts, to improve material distribution.
Plug-assisted forming is generally used for small deep drawn parts.
Plug material, design, and timing can be critical to optimization
of the process. Plugs made from insulating foam avoid premature
quenching of the plastic. The plug shape is usually similar to the
mold cavity, but smaller and without part detail. A round plug
bottom will usually promote even material distribution and uniform
side-wall thickness. For a semicrystalline polymer such as
polypropylene, fast plug speeds generally provide the best material
distribution in the part.
The formed part is cooled in the mold. Sufficient cooling to
maintain a mold temperature of 30.degree. C. to 65.degree. C. is
needed. The part is below 90.degree. C. to 100.degree. C. before
ejection in a desirable embodiment. For the best behavior in
thermoforming, the lowest melt flow rate polymers are
desirable.
Composite Formation
In one embodiment, after thermoforming, the composite of the
laminate and substrate is formed by an injection molding process or
spray process, or other suitable process. In a desirable
embodiment, injection molding is used.
One embodiment of the injection molding process is described as
follows. The shaped laminate is placed into the injection molding
tool. The mold is closed and the substrate material is injected
into the mold. The substrate material has a melt temperature
between 215 and 250.degree. C. in one embodiment, and is injected
into the mold at an injection speed of between 2 and 10 seconds to
obtain the desired adhesion to the laminate in another embodiment.
After injection, the material is packed or held at a predetermined
time and pressure to make the part dimensionally and aesthetically
correct. Typical time periods are from 5 to 25 seconds and
pressures from 200 to 1500 psi. The mold is cooled between 10 and
70.degree. C. to cool the substrate. The temperature will depend on
the desired gloss and appearance needed. Typical cooling time is
from 10 to 30 seconds, depending on part on the thickness. Finally,
the mold is opened and the shaped composite article ejected.
Suitable substrates for injection molding include various grades of
polyethylene (PE) and polypropylene (PP) as shown in Tables 1-4. In
a desirable embodiment, high density polyethylene is injection
molded into the thermoformed laminates described above. In
particular, high density polyethylene may be injection molded into
a formed laminate, the laminate being two layers of ionomer
material and one tie-layer-containing a blend of a EAAT with a
LLDPE and or LDPE.
An embodiment of the invention is a laminate suitable for an impact
and scratch resistant article comprising at least one layer of
ionomer, and a tie-layer, wherein the at least one ionomer layer
and tie-layer are secured to one another by any suitable means to
form a shaped laminate. At least one ionomer layer may pigmented,
desirably a second ionomer layer a' (FIG. 3). The tie-layer may
comprise any one or blend of an acid polymer, soft ionomer, or
polyolefin. The polyolefin, which may also be suitable as a
substrate material, is selected from polyethylene polymers,
polyethylene copolymers, polypropylene polymers, polypropylene
copolymers, polypropylene impact copolymer and a blend of
polypropylene impact copolymer and ethylene plastomer, and mixtures
thereof. Typically, the polyolefin has a 1% secant flexural modulus
of from greater than 1000 MPa.
The laminate may have certain desirable characteristics in flsrther
embodiments. For example, the melt indexes of adjacent laminate
layers are within less than 1 to 4 dg/min of one another. Further,
the at least one ionomer layer may have a 1% secant flexural
modulus of between 150 and 400 MPa in another embodiment. The
tie-layer comprises a blend of an acid terpolymer and a polyolefin,
the polyolefin present in the blend from 30 wt % to 70 wt % of the
blend, and may be blend of ethylene acrylic acid terpolymer and a
polypropylene, or alternately, a blend of ethylene acrylic acid
terpolymer, linear low density polyethylene, and high density
polyethylene.
The laminate may be formed by any suitable technique, such as by
co-extrusion in one embodiment. Further, the laminate may be shaped
by any suitable technique such as by thermoforming the laminate.
Various articles may be formed from the laminate such as automotive
parts and sporting equipment.
In another embodiment, the invention is a composite article
suitable for an impact and scratch resistant article comprising a
laminate comprising at least one layer of ionomer and a tie-layer,
wherein the at least one ionomer layer and tie-layer are secured
one another to form a laminate, and a substrate secured to the
laminate to form the composite article. The tie-layer may comprises
an acid polymer, soft ionomer, polyolefin, and blends thereof. The
substrate may have certain desirable properties, such as a 1%
secant flexural modulus of greater than 1000 MPa in one embodiment.
The polyolefin suitable for the substrate and/or the tie-layer is
selected from polyethylene polymers, polyethylene copolymers,
polypropylene polymers, polypropylene copolymers, polypropylene
impact copolymer and a blend of polypropylene impact copolymer and
ethylene plastomer, and mixtures thereof.
The laminate in this embodiment may have certain desirable
features. For example, the melt indexes of adjacent laminate layers
are within less than 1 to 4 dg/min of one another. Further, the
tie-layer comprises a blend of an acid terpolymer and a polyolefin,
the polyolefin present in the blend from 30 wt % to 70 wt % of the
blend. The tie-layer may also comprise a blend of ethylene acrylic
acid terpolymer and a polyethylene. Further, the tie-layer may
comprise a blend of etheylene ethylene acrylic acid terpolyrner,
linear low density polyethylene, and high density polyethylene.
The laminate may be formed by any suitable technique, such as by
co-extrusion in one embodiment. Further, the laminate may be shaped
by any suitable technique such as by thermoforming the laminate.
The substrate may be contacted with the laminate by any suitable
technique, injection molding in one embodiment. Various articles
may be formed from the laminate such as automotive parts and
sporting equipment.
In a further embodiment of the invention is a composite suitable
for impact and scratch resistant articles formed by the method
comprising first forming a laminate comprising at least two layers
of material; wherein the melt indexes (MI) of adjacent laminate
layers are within 1 to 4 dg/min of one another; followed by forming
the laminate into a shape, the laminate having at least one layer
of ionomer and a tie-layer, wherein the at least one ionomer layer
and tie-layer contact one another to form the laminate; and
finally, securing a substrate layer to the laminate to form the
composite article. The formation of the laminate may be performed
by any suitable technique, such as, for example, co-extrusion. The
shaping step of the laminate may also be performed by any suitable
technique such as, for example, by thermoforming. Further, the
substrate may be secured to the laminate by any suitable technique
such as by injection molding.
End Use Articles
The laminate of the present invention can be used as a
thermoformable sheet where the substrate is either sprayed or
injection molded to couple it with the ionomer/tie-layer laminate
sheet. The composite if formed into the desired shape to form the
article, or composite article. Various types of substrate materials
to form highly desirable articles. The laminate can be used with
plastic substrates such as homopolymers, copolymers, foams, impact
copolymers, random copolymers, and other applications.
Specifically, some articles in which the present invention can be
incorporated are the following: vehicle parts, especially exterior
parts such as bumpers and grills, rocker panels, fenders, doors,
hoods, trim, and other parts can be made from the laminates,
composites and methods of the invention.
Other articles can also be named, for example: counter tops,
laminated surface counter tops, pool liners/covers/boat covers,
boat sails, cable jacketing, motorcycles/snowmobiles/outdoor
vehicles, marine boat hulls/canoe interior and exterior, luggage,
clothing/fabric (combined with non-wovens), tent material, GORETEX,
Gamma-radiation resistant applications, electronics housing (TV's,
VCR's and computers), a wood replacement for decks and other
outdoor building materials, prefab buildings, synthetic marble
panels for construction, wall covering, hopper cars, floor coating,
polymer/wood composites, vinyl tile, bath/shower/toilet
applications and translucent glass replacement, sidings,
lawn/outdoor furniture, appliances such as refrigerators, washing
machines, etc., children's toys, reflective signage and other
reflective articles on roads and clothing, sporting equipment such
as snowboards, surfboards, skis, scooters, wheels on in-line
skates, CD's for scratch resistance, stadium seats, aerospace
reentry shields, plastic paper goods, sports helmets, plastic
microwaveable cookware, and other applications for coating plastics
and metal where a highly glossy and scratch resistant surface is
desirable, while not being subject to algae/discoloration.
Test Methods
Melt Flow Rale (MFR) or Melt Index (MI). Melt flow rate is measured
according to ASTM D1238 test method, at 230.degree. C. and 2.16 kg
load, and is expressed as dg/min or g/10 min. The melt index is
measured according to ASTM D1238 test method, at 190.degree. C. and
2.16 kg load, and is expressed as dg/min or g/10 min. Peak Melting
Temperature. The peak melting temperature (Tm, second melt) of the
polymer was measured by using DuPont Instruments 912 differential
scanning calorimeter (DSC) which is equipped with the standard
numerical analysis software. The area under the melting peak
represents the enthalpy of melt and is reported in Joules per gram
(J/g). Standard procedure involved equilibrating the sample at
0.degree. C., increasing the temperature at a rate of 10.degree.
C./min, to 200.degree. C. (first melt).
Flexural Modulus. The flexural modulus is obtained according to
ASTM D790, with a crosshead speed of 1.27 mm/min, and a support
span of 50.8 mm, using an Instron machine.
90.degree. Adhesion Test. This was done per ExxonMobil Chemical
Company method. First, a cut is made through the laminate to the
substrate in an "X" pattern. Second, the substrate plaque is folded
on the previously scored "X" pattern, the fold being toward the
substrate. Third, insert a razor under the laminate (if possible)
and lift up the razor. Finally, if a corner of the laminate is
lifted, pull at an angle of 90.degree.. The results of these tests
are shown in Tables 2-4 as "Good", which means that there was no
loss or only a very small amount of loss of adhesion between the
substrate and laminate or between laminate layers, and "Poor",
which means that there was loss or substantial loss of adhesion
between either the substrate and laminate or between laminate
layers. A rating of "Fair" means that there was some intermediate
level of adhesion loss. Instrumented Impact. The instrumented
impact strength is measured by ASTM D3763 using a Dynatup Model
8250. A drop weight of 25 pounds (111 N) and a speed of 15 miles
per hour (133 to 400 meters/min) are used to measure the failure
mode and the total energy. The drop weight is adjusted such that
the velocity slowdown is less than 20%. Failure Mode. The failure
mode is defined as ductile (D) if the load vs. displacement curve
is symmetric and there are no radial cracks in the sample and the
tup pierces through the sample. The ductile-brittle (DB) failure
mode is defined as the mode where on the load-displacement curve,
the load goes through the maximum, and rapidly decreases to zero
and there are radial cracks in the sample. And, brittle-ductile
(BD) failure mode is defined as the condition where in the load vs.
displacement curve, the load rapidly decreases and the sample
breaks into multiple pieces. The desirable failure mode is
completely ductile at the specified temperatures.
EXAMPLES
All examples 1-20 were co-extruded sheets made on either a 3 or 4
layer co-extrusion machine. All 3 layer examples were produced on a
Battenfeld Glouster co-extruder machine. All 4 layer examples were
produced at MAYCO Plastics on a HPM co-extruder machine. Each
example comprises the formulation as described in the Tables,
wherein each formulation may be tested for different
properties.
The materials used to make all third and fourth layers were
pre-compounded at ExxonMobil Chemical Baytown Polymers Center in
Baytown, Tex. Pre-compounding was necessary due to the above
mentioned extrusion equipment not having the proper screw design to
adequately mix the polypropylene and polyethylene/acid terpolymer
blends while processing sheet. The tie-layer materials should be
adequately mixed to provide the necessary bond between the laminate
and substrate.
Americhem Corp in Cuyahoga Fall, Ohio, and A. Schulman Corp. in
Birmingham, Mich., provided color pigmentation for the trials.
Colors used for the trials were DCX (DaimlerChrysler) approved
automotive colors white, black, red, and silver metallic.
Pigmentation was provided in a concentrated pellet form with a
blend ratio of 25:1
General processing parameter details for each co-extruded laminate
examples are provided in the previously mentioned process sections
on co-extrusion, thermal forming, and injection molding.
During the co-extrusion trials, the various tie-layers and ionomers
were evaluated and noted as to the ease of processability to
produce a 3 or 4 layer laminate that had the desired gloss level
and color. Compatibility of the various layers' (ionomers',
tie-layers') viscosities to one another in the co-extrusion process
improves the final appearance of the sheet. Large viscosity
differences between layers produced laminates with poor gloss
level, uneven surfaces, poor color depth and dispersion, large
variation in sheet thickness, and areas were layers were even
missing. Changes to the third and forth layers were made based on
the compatibility to the ionomer layers. The melt viscosities (MI)
of each layer were within 2 to 3 MI units (dg/min) of each other.
Composites with the desired appearance and adhesion were in the
range of 2 and 5 MI units (dg/min), such as Examples 1-4.
Adhesion between layers was checked during and after 24 hrs for
each composition using the ExxonMobil modified 90.degree. Adhesion
Test (described above). Layer composition (thickness) was adjusted
accordingly if adequate adhesion was not present during the trials
(not enough tie-layer material). Adhesion testing after 24 hrs, was
done to make sure that there was adequate adhesion to withstand the
stresses induced during the natural, shrinkage that occurs during
the early aging of the composite. It has been shown through testing
that good adhesion may be present initially, but significant
adhesion loss can occur during aging (or annealing) of the
composite even for a relatively short period of time such as 24
hrs.
Impact testing of the sheet was done on 4'' (102 mm) diameter
impact disk molded with ExxonMobil PP8224 as a substrate material.
Examples of the laminate were placed in the injection molding disk
tool, substrate material was injection molded behind the sheet,
cooled, and ejected from the mold. The disks were then tested on a
Dynatup instrumented impact tester at -30.degree. C. at 15 mph (400
m/min).
The results of Examples 1-5 in Table 2 show that blends of an acid
terpolymer and impact copolymer work best as the portion of the
tie-layer (layer 4 in these Examples) that is secured to
polyethylene or polypropylene substrates. Further, these Examples
shown that having a two layer tie-layer works well with a
polypropylene substrate, as in Examples 2 throuoh 4. Adhesion
performance using the acid terpolymer alone as a tie-layer with
polypropylene as the substrate was not as good as when polyethylene
was the substrate.
The results of Examples 6 through 12 in Table 3 show again that a
two layer tie-layer having a blend of the acid terpolymer and a
polypropylene work well. Further, these data shown that, as in
Example 6, that having a tie-layer material of polypropylene (PP
8102E3) that contacts the polypropylene substrate works well under
the Adhesion Test. And, when there is one layer in the tie-layer
such as in Examples 8-12, while there is good adhesion between the
tie-layer and substrate, there is poor adhesion between the ionomer
and tie-layer.
The results of Examples 13 through 20 in Table 4 show that a one
layer tie-layer comprising a blend of materials creates good
adhesion to a polyethylene substrate and the ionomer layers. In
particular, Examples 14-19 all have tie-layers that are blends of
polypropylene or polyethylenes and an acid terpolymer. Also,
Example 20 shows that the acid terpolymer alone works well with the
polyethylene substrate, which is consistent with the results of
Example 1 using a different grade of acid terpolymer.
While the present invention has been described and illustrated by
reference to particular embodiments, those of ordinary skill in the
art will appreciate that the invention lends itself to many
different variations not illustrated herein. For these reasons,
then, reference should be made solely to the appended claims for
purposes of determining the true scope of the present
invention.
Terms that are or may be trademarked in some jurisdictions are used
in the description. These terms are written in all capital letters,
and is understood to recognize such trademarks. For brevity,
markings such as ".TM." or ".RTM." have not been used, and in the
tables, the terms ESCOR, ESCORENE etc, are not used in all.
All priority documents are herein fully incorporated by reference
for all jurisdictions in which such incorporation is permitted.
Further, all documents cited herein, including testing procedures,
are herein fully incorporated by reference for all jurisdictions in
which such incorporation is permitted.
TABLE-US-00001 TABLE 1 Description and properties of commercially
available materials Melt Index or 1% Secant Flex. Peak Melt temp.
Melt Flow Rate Modulus (MPa) Material Description (.degree. C.)
(dg/min) [ASTM D-790] IOTEK 7030 Zn salt of 85 2.5 (MI) 155
(ExxonMobil) ethylene acrylic acid copolymer IOTEK 7510 Zn salt of
67 1.2 (MI) 35 (ExxonMobil) ethylene acrylic acid copolymer IOTEK
7520 Zn salt of 67 2.0 (MI) 30 (ExxonMobil) ethylene acrylic acid
copolymer IOTEK 8000 Na salt of 83 0.8 (MI) 320 (ExxonMobil)
ethylene acrylic acid copolymer ESCORENE Polypropylene 162 2.0
(MFR) 22930 PP 8102E3 impact (ExxonMobil) copolymer ESCOR AT 320
Ethylene acrylic 76 5.0 (MI) 19 (ExxonMobil) acid terpolymer (EAAT)
ESCOR AT 310 Ethylene acrylic 76 6.0 (MI) 60 (ExxonMobil) acid
terpolymer (EAAT) ESCORENE HD High Density 135 0.43 (MI) 1450 9856B
polyethylene (ExxonMobil) (HDPE) EXCEED metallocene 115 3.5 (MI) --
357C32 catalyzed Linear (ExxonMobil) Low Density Polyethylene
(mLLDPE) ESCORENE Linear Low 123 50 (MI) 214 LL6201 Density
(ExxonMobil) Polyethylene ESCORENE HD High Density 136 8.2 (MI) 827
6908 Polyethylene (ExxonMobil) (HDPE) PP 8224 Polypropylene 162 25
(MFR) 1034 (ExxonMobil) impact copolymer ExxonMobil Polypropylene
162 4 (MFR) 980 PP7032E2 impact copolymer
TABLE-US-00002 TABLE 2 Multilayer co-extruded film formulations for
polyethylene and polypropylene substrate composites Instrumented
Impact @ 30.degree. C. & 90.degree. Adhesion Example Layer 3
Layer 4 15 mph Test.sup.1 Number Layer 1 Layer 2 (wt %/wt %) (wt
%/wt %) (400 m/min) PE.sup.2 PP.sup.3 1 IOTEK IOTEK AT320 -- --
Good Poor 8000 7030 2 IOTEK IOTEK AT320 PP 8102E3/AT320 5 ductile
-- Good 8000 7030 (50/50) 3 IOTEK IOTEK AT320 PP 8102E3/AT320 5
ductile -- Good.sup.4 8000 7030 (60/40) 4 IOTEK IOTEK PP
8102E3/AT320 PP 8102E3/AT320 5 ductile -- Good 8000 7030 (50/50)
(60/40) 5 IOTEK IOTEK PP 8102E3/AT320 PP 8102E3/AT320 5 ductile --
Fair.sup.5 8000 7030 (60/40) (50/50) .sup.1The test is as described
in the text. "Good" means that there was no loss of adhesion
between the substrate and laminate or between laminate layers.
"Poor" means that there was loss of adhesion between either the
substrate and laminate or between laminate layers.
.sup.2Polyethylene is the substrate. .sup.3Polypropylene, PP 8224,
is the substrate. .sup.4Some separation between the 2nd and 3rd
layers. .sup.5Some separation between the 3rd and 4th layers.
TABLE-US-00003 TABLE 3 Multilayer co-extruded film formulations for
polypropylene substrate composites Example Layer 3.sup.1 Layer 4
Number Layer 1 Layer 2 (wt %/wt %) (wt %/wt %) 90.degree. Adhesion
Test to PP.sup.2 6 IOTEK IOTEK PP 8102E3/AT320 (50/50) PP 8102E3
Good adhesion to PP 8000 7030 substrate 7 IOTEK IOTEK PP
8102E3/AT320 (40/60) PP 8102E3/AT320 Good adhesion to PP 8000 7030
(50/50) substrate 8 IOTEK IOTEK PP 8102E3/AT320 (67/33) -- Poor
adhesion to ionomer, 8000 7030 Good adhesion to PP substrate 9
IOTEK IOTEK PP 8102E3/AT320 (65/35) -- Poor adhesion to ionomer,
8000 7030 Good adhesion to PP substrate 10 IOTEK IOTEK PP
8102E3/AT320 (60/40) -- Poor adhesion to ionomer, 8000 7030 Good
adhesion to PP substrate 11 IOTEK IOTEK PP 8102E3/MD353D -- Poor
adhesion to ionomer - 8000 7030 (90/10) Delamination, Good adhesion
to PP substrate 12 IOTEK IOTEK PP 8102E3/MZ203D (90/10) -- Poor
adhesion to ionomer - 8000 7030 Delamination, Good adhesion to PP
substrate .sup.1MD 353D and MZ203D are Fusabond Products from Du
Pont; PP 8102E3 is ExxonMobil's PP 8102E3 AT320 is ExxonMobil's
ESCOR AT320 as in Table 1. .sup.2The test is as described in the
text. "Good" means that there was no loss of adhesion between the
substrate and laminate or between laminate layers. "Poor" means
that there was loss of adhesion between either the substrate and
laminate or between laminate layers.
TABLE-US-00004 TABLE 4 Multilayer co-extruded film formulations for
polyethylene composites Example Layer 3.sup.1 Number Layer 1 Layer
2 (wt %/wt %) 90.degree. Adhesion Test to PE.sup.2 13 IOTEK 8000
IOTEK 7030 A1B1 (75/25) Poor adhesion to substrate 14 IOTEK 8000
IOTEK 7030 A1B1 + Good adhesion to ionomer and HDPE 6908 substrate
15 IOTEK 8000 IOTEK 7030 A2B1 - Good adhesion to ionomer and HDPE
6908 substrate 16 IOTEK 8000 IOTEK 7030 A2B1 + Good adhesion to
ionomer and HDPE 6908 substrate 17 IOTEK 8000 IOTEK 7030 A1B2 -
Good adhesion to ionomer and HDPE 6908 substrate 18 IOTEK 8000
IOTEK 7030 A1B2 + Good adhesion to ionomer and HDPE 6908 substrate
19 IOTEK 8000 IOTEK 7030 A2B2 + Good adhesion to ionomer and HDPE
6908 substrate 20 IOTEK 8000 IOTEK 7030 B2 Good adhesion to ionomer
and HDPE 6908 substrate .sup.1A1: ESCORENE HD9856/ESCORENE LL 6201
(85/15 wt %); A2: EXCEED 357C32; B1: ESCOR AT320; B2: ESCOR AT310.
The meaning of the "+" and "-" symbols are as follows: (+) is 65 wt
% ESCOR 320 or 310; (-) is 35 wt % ESCOR AT320 or 310. .sup.2The
test is as described in the text. "Good" means that there was no
loss of adhesion between the substrate and laminate or between
laminate layers. "Poor" means that there was loss of adhesion
between either the substrate and laminate or between laminate
layers.
* * * * *